1. Field of the Invention
The present invention relates generally to a hermetic compressor for use in a refrigerant cycle, and more particularly, to a casing of a hermetic compressor contributing to reduction of vibration and noise produced from the hermetic compressor.
2. Description of the Prior Art
Following a refrigerant cycle, a conventional hermetic compressor draws in low temperature and low pressure vapor refrigerant from an evaporator and compresses it into high temperature and high pressure vapor refrigerant, and then discharges the refrigerant to a condenser.
FIG. 1 shows the structure of such conventional hermetic compressor. Referring to FIG. 1, the hermetic compressor includes a motor, a cylinder, a casing 50 partitioning a compressor body 10 from the outside environment, and a supporting member 30 for supporting the compressor body 10. The compressor body 10 contains therein a suction/discharge pipe and draws in and compresses refrigerant.
The motor is comprised of a stator 12 secured on the supporting member 30 and a rotor 14 rotating inside of the stator 12. A rotary shaft 16 is mounted in and attached to the center of the rotor 14, and an eccentric portion 18 is formed at the lower end of the rotary shaft 16.
The cylinder includes a cylinder body 22 that defines a bore 23 for the refrigerant suction/compression, and a valve 26 disposed on the upper portion of the cylinder body 22 to control the refrigerant suction/discharge. A piston 24 is assembled in the cylinder body 22 to be reciprocally movable therein. The piston 24 is connected to a connecting rod 20 connected to the eccentric portion 18 that converts the rotary motion of the rotary shaft 16 into linear reciprocal motion.
The suction/discharge pipe 28 connects the valve 26 of the cylinder to the refrigerant cycle, and define a passageway through which refrigerant is drawn in and discharged out.
The supporting member 30 is disposed inside of a lower shell 54 of the casing 50 and supports the stator 12 and the cylinder body 22 of the motor, thereby partitioning the compressor body 10 off from the casing 50. The supporting member 30 is formed of a spring so as to absorb vibration produced during a rotation of the eccentric portion 18 and reciprocal movement of the piston 24.
The casing 50 encloses the compressor body 10 from outside, and is comprised of an upper shell 52 and the lower shell 54 for easy assembling. The supporting member 30 is disposed in the lower shell 54, and the compressor body 10 is mounted on the supporting body 30. The lower shell 54 has an aperture through which the suction/discharge pipe 28 extends. For simplicity of the fabricating process and strength of the casing 50, the upper and lower shells 52 and 54 of the casing 50 are made by molding of a metal plate. The upper and lower shells 52 and 54 are connected to each other, for example, by welding.
When the supply of electricity is provided to the hermetic compressor constructed as above, the rotor 14 starts rotating. With the rotation of the rotor 14, the rotary shaft 16, which is integrally attached to the rotor 14, also rotates. And, as the rotary shaft 16 rotates, the piston 24 starts reciprocating in the cylinder body 22 by motion of the eccentric portion 18 and the connecting rod 20 at the leading end of the rotary shaft 16. By reciprocating the piston 24 inside of the bore 23, the valve 26 is moved to permit the refrigerant to be drawn in through the suction/discharge pipe 28 for compression and to be discharged out to the refrigerant evaporator cycle. More specifically, as the piston 24 moves toward the lower dead end, the suction valve 29 opens, permitting the low temperature and low pressure gaseous refrigerant into the cylinder bore 23 via the suction pipe (not shown). Then as the piston 24 moves toward the upper dead end, the suction valve 29 closes, and the refrigerant in the bore 23 is compressed. After the compression of the refrigerant, the discharge valve 27 opens, permitting the compressed refrigerant to be discharged toward the condenser via the discharge pipe 28. During the rotation of the rotary shaft 16, the piston 24 keeps reciprocally moving up and down between the upper and lower dead ends, repeating the refrigerant cycle described above.
As described above, the rotor 14 rotates, and the rotary motion of the rotor 14 is converted to the reciprocal movement of the piston 24 by the eccentric portion 18 and the connecting rod 20 during the cycle of refrigerant suctioning, compressing and discharging in the compressor body 10. Accordingly, a considerable amount of vibration and noise is produced. The supporting member 30 is provided for absorbing, and thus reducing, the vibration and noise from the compressor body 10. However, the vibration and noise is not completely absorbed, thus annoying vibration and noise is transmitted to the outside via the casing 50.